Geodesic
The Pedal Surfaces of (1,2)-Congruences with a One-Parameter Set of Ellipses
Journal for geometry and graphics, Tome 1 (1997) no. 2, pp. 135-15.

Voir la notice de l'article provenant de la source Heldermann Verlag

In the 3-dimensional Euclidean space (the model of the 3-dimensional projective space) among the surfaces of 4th order with a nodal line those through the absolute conic are extracted as a special class which contains the pedal surfaces of (1,2)-congruences. One class of these surfaces is classified with regard to the number and types of their real singular points. These surfaces have been visualized using the program Mathematica 3.0. 
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S. Gorjanc. The Pedal Surfaces of (1,2)-Congruences with a One-Parameter Set of Ellipses. Journal for geometry and graphics, Tome 1 (1997) no. 2, pp. 135-15. http://geodesic.mathdoc.fr/item/JGG_1997_1_2_a3/